\begin{tikzpicture}
    \tkzDefPoints{0/0/B,  3.0/0/C,  2.5/2/A}
    \tkzFindAngle(C,B,A)  \tkzGetAngle{b}
    \tkzDefPointBy[rotation=center C angle -\b](B)  \tkzGetPoint{d}
    \tkzInterLL(C,d)(A,B)  \tkzGetPoint{D}

    \tkzDrawPolygon(A,B,C)
    \tkzDrawSegment[dashed](C,D)
    \tkzMarkAngles[size=0.4](C,B,A  D,C,B)
    \tkzLabelPoints[above](A)
    \tkzLabelPoints[below](B,C)
    \tkzLabelPoints[left](D)
\end{tikzpicture}

